Self-leveling step-ladder.



A. J. JUDGE.

SELF LEVELING STEP LADDER. APPLICATION FILED AUG.11,1913

1,1 17,496. Patented Nov. 17, 1914.

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SELF LEVELING STEP LADDER.

APPLICATION FILED AUG. 11, 1913. 1,1 1 7,496. Patented Nov. 17, 1914.

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THE NORRIS PETERS 60., PHO

ARTHUR J. JUDGE, OF ST. LOUIS, MISSOURI.

SELF-LEVELING STEP-LADDER.

Specification of Letters Patent.

Patented Nov. 17, 1914.

Application filed August 11, 1913. Serial No. 784,016.

To all whom it may concern:

Be it, known; that I,- ARTHUR J. JUDGE, a citizen of the United States, and a resident of the city of St. Louis and State of Missouri, have invented a new and useful Tmprovement in Self-Leveling Step-Ladders, of which the following is a specification.

This invention'relates to step ladders of the type having a ladder section and legs or props pivoted thereto for supporting the ladder independently of a fixed support, such as a wall.

The object of this invention is a fourlegged step-ladder which will adapt itself automatically to any unevenness in the ground or other surface upon which it may be set up.

The invention consists in a step-ladder provided with props or legs pivoted to the ladder portion and rigidly braced against sidewise movement, the two legs being freely slidable up and down relatively to their pivots, and connected to each other in such manner that when one slides up the other slides down an equal distance, whereby they accommodate themselves to uneven supporting surfaces.

Further objects of the invention appear in connection with the description of the embodiment thereof shown in the accompanying drawings, and in what the invention consists is particularly pointed out in the appended claims.

In the drawings, in which like characters designate like parts wherever used, Figure 1 is a side view of a step-ladder embodying the invention; Fig. 2 is a back view of the same; Fig. 3 is an enlarged view of the top portion of a slidable leg, showing the pivot fittings and equalizing gearing; Fig. 4 is a side view of the same looking from the inner side of the leg; Figs. 5 and 6 are cross sections of a sliding leg taken on the lines 55 and 66, respectively, looking in the direction of the arrows; Fig. 7 is an enlarged cross section through the sliding legs taken on the line 77 in Fig. 2, looking in the direction of the arrows, and showing the gears and shaft in plan view; Fig. 8 is an enlarged cross section through a sliding leg taken on the line 88 in Fig. 2, looking in the direction of the arrows; and Fig. 9 is a view of a modification of the construction shown in Figs. 3 to 6, whereby the legs can be clamped in adjusted position.

Referring to the drawings, the step-ladder comprises a ladder section 11 having steps 12, and a platform 13 rigidly secured to the ladder portion at its top. The legs or props 14 are slidable in metal boxings 15 which are pivoted tobrackets 16 secured below the platform. The lower ends of the legs slide through straps 17 at the ends of a cross-bar 18. This cross-bar is supported and braced from the boxings 15 by means of diagonal slats 19 securely fastened at their upper ends to lugs 20 formed integral with the boxings 15. A cross rod 21 connects the lugs 20 of the two boxings and braces the top ends of the sliding legs against sidewise movement.

The upper ends of the props are fitted with toothed racks 22 which slide in the boxings. One of these racks faces to the front and the other faces to the rear, and they mesh with the opposite sides of two pinions 28 fixed to the ends of the horizon tal rod 24 journaled in the two boxings. By reason of this arrangement, when there is no weight on the step-ladder one prop may be raised and the other prop lowered simultaneously and by equal amounts, thereby enabling the step-ladder to adjust itself to uneven floors or other surfaces upon which it may be set up. Any weight upon the step-ladder tends to cause both props to slide upward in the boxings, and, as the racks engage on opposite sides of the pinions, any simultaneous movement of both props upward is thereby prevented, whatever the relative position of the two props with respect to each other.

The boxing 15 may be provided with a clamp bolt 26 and lever nut 27, as shown in Fig. 9, if it is desired to clamp the sliding legs from movement after the step-ladder is set up. In views 1, 2, 3, 4 and 6, rivets 25 are shown for retaining the sliding legs in the boXings instead of the clamp bolt 26, because the clamp bolt is found not to be necessary to the successful use of the device.

It is evident that changes in the details of construction of my device may be made without departing from my invention, and I do not restrict my invention to the embodiment thereof shown and described herein.

What I claim as my invention is as follows:

1. A self-adjusting device for parallel slidable legs, guides for said legs, racks carried by said legs on opposite sides thereof,

and pinions meshing with said racks, said pinions being secured to a transverse shaft mounted in said guides.

2. A self-leveling step ladder comprising a rigid ladder, swinging guides pivoted to said ladder near its top, two props slidably arranged in said guides, racks secured to said props on opposite sides thereof and a shaft rotatably mounted in said guides and carrying pinions at 1 its ends meshing with said racks respectively, and means for retaining said props in said guides. 1

, A self-leveling step ladder comprising airigid ladder, a swingingframe pivoted, to 1 said ladder near its top, two props slidably arranged in'said'frame, said frame having cross braces for the lower ends of said props, a rack secured to the front edge of one of saidprops, a similar rack secured to the back edge of the other prop, and a shaft rotatably mounted in said frame and carrying' pinions at its ends meshing with said ;raeks respeetivel-y Signed at St. Louis, Missouri, this 8th day of August, 1913. 1

ARTHUR J; JUDGE;

Witnesses: v

AMAsA M. HOLCQMBE, A ANDREW P. KEssLINe;

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0. 

